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How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and amazing filter technology to make the delicious coffee we enjoy. What exactly is it that makes it work?

To make an espresso, hot water is forced under high pressure through finely ground coffee. The process is similar to making drip coffee, but the difference is in the pressure.

The Group Head

As the name implies, the group head is where you place your portafilter when making espresso. It is responsible for dispersing water into the portafilter before controlling the pressure that results from the extraction. There are many different kinds of group head each with its distinct advantages and disadvantages. Some are focused on temperature stability, others on pre-infusion capabilities, while others are designed to control the lever. There are even some that include a mix of features, such as the E61 one, which is the standard choice for many baristas due to its ability to provide multiple benefits in one package.

As you can see from the picture above, the group head is equipped with several notches. You can place your portafilter inside these notches, and then twist the head to lock it. There is also a gasket made from rubber which is located inside the notches and helps to create a seal when you insert your portafilter into the machine. The notches on the head allow for a precise placement of the portafilter, which is essential to ensure a consistent extraction.

Apart from allowing you easily insert your portafilter, the group head is also responsible to maintain an even temperature. It does this by cycling hot water through the brew basket, and around the portafilter to ensure that it is always at the correct temperature to extract. This is important because even a few degrees can mean the difference between good and excellent espresso.

The Pump

The motorized pumps used in espresso machines rotary provide nine atmospheric bar pressure required to extract espresso. This differs from manual piston machines that rely on levers. This pressure is built up by pumping water through a heat-exchanger and then through the ground coffee.

Pumps are typically less expensive than piston-driven machines and tend to last longer. However, both types of machines can be damaged by excessive use and inadequate cleaning. Pumps are also more complex mechanically, which can increase the cost of even simpler models.

Certain espresso machines eliminate the pump completely and instead employ steam pressure to create espresso. The drawback of this is that the boiler that produces steam also raises the temperature of water to boiling which can cause over-extraction. The machines must also constantly rebuild their pressure in between cups. This takes energy and time.

Many espresso machines use the rotary or vibration pump. A vibration model employs an oscillating disk to create pressure, whereas the circular model pushes hot liquid through the ground at a rapid speed. Both machines can produce excellent espresso but rotary machines are quieter, more durable and less likely to break.

The Boiler

The boiler is the part that heats the water to the optimal temperature to extract. The steam that is created gets to the portafilter which contains the espresso coffee machines espresso grounds. It is then pumped into the cup. The steam is able to create enough pressure to push the grounds of coffee through. This results in a crema on top of the Discount espresso machines (userbookmark.com). This is one of the hallmarks of a great espresso.

There are three distinct types of best espresso machine under 500 machines, each having different pumps and the temperature of the brew. There are different ways that the brew can be controlled and the dimensions of the cup the machine is capable of making.

The first espresso machines were steam-types. They had only one boiler to make both brew and steam, however, the pressure they could generate was low - only two bars of atmospheric pressure maximum. This resulted in the coffee tasting bitter and burnt. The modern espresso machine was created by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most popular espresso maker is a semi-automatic device that has an electric pump. This is what people envision when they think of an espresso machine. Semi-automatic machines require you to grind and tamp the beans on your own however the pump controls the water flow and pressure. This is a great compromise between the human touch and the mechanised quality.

The Filter

Espresso machines typically have filters that separate the grounds of coffee from hot water. The filter is also an important part of the temperature control system, as it prevents the machine from overheating.

A filter also helps with flavor, as it permits a longer flowering period. This lets the beans release their flavors, and improves extraction.

However it is crucial to keep in mind that even a great filter can produce a bad cup of coffee, because the quality espresso machine of the beans and extraction are vital.

It's here that the magic takes place. This is the reason why espresso tastes so delicious. The grouphead, sometimes called the brewhead, is where the portafilter (the container you place the coffee grounds into) is located when you're making espresso.

Steam-driven espresso machines use hot water that is heated in an airtight container to make steam. The steam then pushes hot water through coffee grounds under high pressure. These types of machines are usually cheaper and easier to maintain than pump-driven models. They are however limited in their ability to create the perfect conditions for brewing as they only operate with 1-1.5 bar of pressure. The perfect shot requires 9 bar espresso machine-10 bars.

In recent years, compressed air-driven espresso machines have become more popular. They utilize an air compressor to push hot water through the ground and are much more mobile than steam-driven electric espresso machines.